Merge branch '1.6' into 1.7

.gitmodules

README.FreeBSD

cmake/thread.cmake

src/box/box.cc

src/box/cluster.cc

src/box/lua/net_box.c

src/box/lua/net_box.lua

src/box/lua/snapshot_daemon.lua

src/box/memtx_engine.cc

src/box/tuple.cc

src/box/vclock.h

src/box/xrow.h

test/box/errinj.result

test/box/net.box.result

test/box/net.box.test.lua

test/box/schema_reload.result

test/box/schema_reload.test.lua

test/box/suite.ini

test/box/upsert_errinj.result

test/box/upsert_errinj.test.lua